Medical advances sometimes breed new categories of relationships. The arrival of organ donation, for example, created a link between individuals that hadn’t existed before. The terra incognita that makes up a fortysomething couple’s bond with their 25-year-old egg donor—their idealistic, eager-to-please step-niece—is explored in writer-director Tamara Jenkins’ new fertility drama, Private Life. Inspired in part by Jenkins’ own fertility treatments, the wry, unsparing film—premiering Friday on Netflix—finds its main characters wandering without a map, possibly uncertain why they’re there in the first place.

Crucially, we’re never sure why 41-year-old Rachel (Kathryn Hahn) and 47-year-old Richard (Paul Giamatti) want a child. That detail robs the artsy couple—she a playwright and author, he a once-celebrated theater director now selling artisanal pickles—of easy sympathy. Their packed yet empty-feeling apartment in a still-ungentrified corner of the East Village doesn’t feel like a financial sacrifice for the next generation so much as it does the natural outcome for a couple that never planned far enough ahead to create a home for themselves. Clearly smug about having had her two daughters early, Richard’s suburban sister-in-law Cynthia (Molly Shannon) is casually scathing when she discovers that the couple have resumed fertility treatment—and that they need an urgent loan of $10,000 for their latest procedure. “They’re like fertility junkies,” diagnoses Cynthia, not incorrectly. When Rachel and Richard tire of gambling their savings on reproductive Hail Marys, their single-mindedness leads them to ask for an egg from the young woman most likely to say yes: Cynthia’s daughter Sadie (Kayli Carter).

Even before the three of them decide to have a baby together, Rachel and Richard’s relationship with their (non-biological) niece is beset with emotional landmines. A very young 25—her callow, narcissistic comments wouldn’t be out of place in the mouth of Hannah Horvath—Sadie aspires to write and looks to the couple as role models while working on the last of her college credits. (The curly-haired, croaky-voiced Carter bears a remarkable resemblance to a teenage Natasha Lyonne, whose first leading role was in Jenkins’ debut feature, The Slums of Beverly Hills.) Sadie comes to live with Rachel and Richard in the city, quickly becoming something between friend, daughter, protégé, foil, and possible rival. (Hahn’s eyes deaden when Sadie unthinkingly refers to their planned child as “our baby.”) Private Life sensitively guides viewers through the trio’s unanticipated peaks and valleys. The couple’s efforts to keep Sadie happy are forced into a pause when the young woman badmouths her parents. They’re grateful for their niece’s sacrifice, which means they have to bite their tongues each and every time Sadie accidentally insults them to their faces while chewing a mouthful of food they paid for.

Because Jenkins doesn’t endow Rachel and Richard’s desire for children with any sort of higher purpose, we’re simply asked to observe what that all-consuming aspiration does to their relationships, especially their marriage. We first meet the couple in bed, with Richard surveying his wife’s ass to locate its “upper outer quadrant,” into which he’ll inject the latest round of unpronounceable substances. The couple’s desperation makes them vulnerable to predation, while making them feel like they, too, are “preying on the bodies of random young women.” We don’t have a strong idea of what they were like as a couple before their zeal to have kids overtook them, but Cynthia is all too believable when she says that their marriage is dysfunctional and has been for a while. The film increasingly makes us wonder whether they should have kids at all, while continuing to empathize with their feelings of bereftness.

Private Life is certainly very good at shivving its characters at close range and gutting these dyspeptic, privileged white people when they deserveit.

Private Life is the kind of movie in which every decision appears to have been made with a Wes Anderson­–esque obsessive attention to detail. Characters have ages, Rachel and Richard’s apartment sits on a specific street, and Sadie gets a hometown (Scarsdale) and a college (Bard). In other words, Jenkins creates a notable sense of specificity—one that defines precisely who her characters are but makes them somewhat repellent in their self-imposed confines, too.

Private Life’s early scenes, in which Rachel pursues treatment for her own ova, immerse the viewer in the sorrows and surrealities of in vitro fertilization. Jenkins underscores the sci-fi–like qualities of this cutting-edge technology, or at least its packaging—an impression drolly undercut by the failure of each and every procedure. (Denis O’Hare plays their ever-optimistic doctor.) In the clinic’s waiting room, sitting next to their grim-faced male partners in street clothes, the women don bright blue mesh caps, matching ID bracelets, and body-morphing gowns—accouterments that wouldn’t look out of place around the examination table aboard a UFO. Amid the shots of chartreuse polka dots on Rachel’s stomach—nickel-size bruises from daily hormone injections—emerges the profound alienness of what she undergoes to enjoy a pleasure so many others take for granted.

Jenkins is just as skilled and sharp in re-creating Rachel and Richard’s milieu—the kind of world where the artist’s community Yaddo and the literary magazine Tin House are household names. (Indeed, you’d have to know not only what Tin House is but what its stature is to fully understand a joke at the expense of a character who’s less enmeshed in that world.) We’re a long way from the heyday of Woody Allen’s romanticizations of the Manhattan literati; these days, we’re more likely to see the self-lacerating portraits of the same set by Noah Baumbach. But there’s no denying that that critique-what-you-know approach can add up to a kind of myopia, too. Private Life is certainly very good at shivving its characters at close range and gutting these dyspeptic, privileged white people when they deserve it. Save for Sadie’s charmed fate, I can’t fault Private Life for nailing what it sets out to accomplish. But its cultural narrowness, however well-expounded, also left me wondering about the trials and tribulations of all the other couples in that waiting room long after we’d seen the last of them.